Add file matcher to releasenotes promote job

We can only promote content when it was generated, so add the same file
matcher to the promote job that the gate job uses.

Change-Id: I67a94af985580574adb00571abc61e3697bcd465

zuul.d/jobs.yaml

@@ -423,6 +423,15 @@
       - secret: afsdocs_secret-releasenotes
         name: afs
         pass-to-parent: true
+    # Same file list as for job build-reno-releasenotes that is
+    # defined in zuul/zuul-jobs repo, file zuul.d/python-jobs.yaml.
+    # Keep those lists in sync.
+    files:
+      - ^releasenotes/.*
+      - bindep.txt
+      - doc/requirements.txt
+      - test-requirements.txt
+      - tox.ini
 
 - job:
     name: publish-openstack-releasenotes